Question

If atmospheric pressure suddenly changes from 1.00 atm to 0.892 atm at 298 k, how much oxygen will be released from 4.40 l of water in an unsealed container?

Answer 1

Henry's law constant for oxygen is 0,0013 mol/L·atm. Air has 21,0% oxygen.
concentration of oxygen at 1 atm: 0,0013 mol/L·atm · 0,21 · 1 atm = 0,000273 mol/l.
concentration of oxygen at 1 atm: 0,0013 mol/L·atm · 0,21 · 0,892 atm = 0,000243 mol/l.
difference in concentration: 0,000273 - 0,000243 = 0,00003 mol/L.
n(oxygen) = 0,00003 mol/L · 4,40 L = 0,000132 mol.